Integrity rules in the system tables

Chapter 18. Ensuring Data Integrity
Integrity rules in the system tables

All the information about integrity checks and rules in a database is held in the following system tables:

System table Description

SYS.SYSTABLE CHECK constraints are held in the view_def column of SYS.SYSTABLE. For views, the view_def holds the CREATE VIEW command that created the view. You can check whether a particular table is a base table or a view by looking at the table_type column, which is BASE or VIEW respectively

SYS.SYSTRIGGER Referential integrity actions are held in SYS.SYSTRIGGER. The referential_action column holds a single character indicating whether the action is cascade (C), delete (D), set null (N), or restrict (R). The event column holds a single character specifying the event that causes the action to occur: a delete (D), insert (I), update (U), or update of column-list (C). The trigger_time column shows whether the action occurs after (A) or before (B) the triggering event

SYS.SYSFOREIGNKEYS This view presents the foreign key information from the two tables SYS.SYSFOREIGNKEY and SYS.SYSFKCOL in a more readable format

SYS.SYSCOLUMNS This view presents the information from the SYS.SYSCOLUMN table in a more readable format. It includes default settings and primary key information for columns

System table	Description
SYS.SYSTABLE	CHECK constraints are held in the view_def column of SYS.SYSTABLE. For views, the view_def holds the CREATE VIEW command that created the view. You can check whether a particular table is a base table or a view by looking at the table_type column, which is BASE or VIEW respectively
SYS.SYSTRIGGER	Referential integrity actions are held in SYS.SYSTRIGGER. The referential_action column holds a single character indicating whether the action is cascade (C), delete (D), set null (N), or restrict (R). The event column holds a single character specifying the event that causes the action to occur: a delete (D), insert (I), update (U), or update of column-list (C). The trigger_time column shows whether the action occurs after (A) or before (B) the triggering event
SYS.SYSFOREIGNKEYS	This view presents the foreign key information from the two tables SYS.SYSFOREIGNKEY and SYS.SYSFKCOL in a more readable format
SYS.SYSCOLUMNS	This view presents the information from the SYS.SYSCOLUMN table in a more readable format. It includes default settings and primary key information for columns

For a description of the contents of each system table, see the chapter "SQL Anywhere System Tables". You can use Sybase Central or ISQL to browse these tables and views.